The Spit Stain is a natural occurrence created by people living in unnatural settings and falls under the study of garbology. (introduction, Classification of a Spit Stain)

The photo/book project Classification of a Spit Stain is a study of sidewalk stains in various cities in the world but in particular New York. Having a tendency to look down when I walk in cities, I began to notice the different stain and spill patterns on the sidewalks. Around the same time I was reading about garbology—a developing scientific field that combines anthropological and archeological techniques to study human detritus and waste patterns in order to determine the social conditions of a given time period. Under this influence I invented a classification system for the stains and spills I found on the sidewalks, taking field notes on each stain I encountered and photographed.